Bottom Line:
Understanding the physical demands placed upon the musculoskeletal system by individual postures may allow experienced instructors and therapists to develop safe and effective yoga programs which reduce undesirable side effects.They then performed the asanas in a motion analysis laboratory.Profiles illustrating the postures and including the biomechanical data were then generated for each asana.

ABSTRACTUnderstanding the physical demands placed upon the musculoskeletal system by individual postures may allow experienced instructors and therapists to develop safe and effective yoga programs which reduce undesirable side effects. Thus, we used biomechanical methods to quantify the lower extremity joint angles, joint moments of force, and muscle activities of 21 Hatha yoga postures, commonly used in senior yoga programs. Twenty older adults, 70.7 years ± 3.8 years, participated in a 32-wk yoga class (2 d/wk) where they learned introductory and intermediate postures (asanas). They then performed the asanas in a motion analysis laboratory. Kinematic, kinetic, and electromyographic data was collected over three seconds while the participants held the poses statically. Profiles illustrating the postures and including the biomechanical data were then generated for each asana. Our findings demonstrated that Hatha yoga postures engendered a range of appreciable joint angles, JMOFs, and muscle activities about the ankle, knee, and hip, and that demands associated with some postures and posture modifications were not always intuitive. They also demonstrated that all of the postures elicited appreciable rectus abdominis activity, which was up to 70% of that induced during walking.

Mentions:
Once instrumented, the participants performed the asana sequences, guided by their instructor (Figure 1). Sequences were the same as those used during the regular yoga classes. A firm but portable clear Plexiglas wall was positioned for wall support in the lab visits. The clear wall permitted the capture of the markers. We decided a priori to examine the asanas while the participants were holding the poses in a static position; this provides information regarding the physical demands of the postures themselves. For each posture, the participant began in a starting position, moved smoothly into the posture, held the posture while taking one full breath, and then returned back to the original position. The instructor provided visual cues by demonstrating the postures simultaneously. Once the participant moved into the position, the instructor provided a verbal cue to the research associate to initiate the 3-second data collection. Two trials of each asana were collected. For postures that involved asymmetric positioning of the 2 support limbs (e.g., side stretch, crescent, and warrior asanas), the postures were done twice—initially with the dominant limb in the front (leading) position and subsequently in the back (trailing) position. The JMOFs varied considerably between the leading and trailing limbs; thus, they were considered separately. Consequently, side stretch, crescent, and warrior asanas were subdivided into leading- and trailing-limb postures (e.g., crescent front and crescent back). The participants also completed 2 walking trials at their self-selected speed, in order to provide a reference condition, that is, walking is a well-studied, stereotypical activity about which we have a lot of biomechanical data as well as a common intuitive understanding of demand. To provide a standardized frame of reference, the EMG measured during each posture was “normalized” to the EMG that resulted from walking, by dividing the maximum EMG signal developed during the posture on the maximum EMG signal invoked during walking.

Mentions:
Once instrumented, the participants performed the asana sequences, guided by their instructor (Figure 1). Sequences were the same as those used during the regular yoga classes. A firm but portable clear Plexiglas wall was positioned for wall support in the lab visits. The clear wall permitted the capture of the markers. We decided a priori to examine the asanas while the participants were holding the poses in a static position; this provides information regarding the physical demands of the postures themselves. For each posture, the participant began in a starting position, moved smoothly into the posture, held the posture while taking one full breath, and then returned back to the original position. The instructor provided visual cues by demonstrating the postures simultaneously. Once the participant moved into the position, the instructor provided a verbal cue to the research associate to initiate the 3-second data collection. Two trials of each asana were collected. For postures that involved asymmetric positioning of the 2 support limbs (e.g., side stretch, crescent, and warrior asanas), the postures were done twice—initially with the dominant limb in the front (leading) position and subsequently in the back (trailing) position. The JMOFs varied considerably between the leading and trailing limbs; thus, they were considered separately. Consequently, side stretch, crescent, and warrior asanas were subdivided into leading- and trailing-limb postures (e.g., crescent front and crescent back). The participants also completed 2 walking trials at their self-selected speed, in order to provide a reference condition, that is, walking is a well-studied, stereotypical activity about which we have a lot of biomechanical data as well as a common intuitive understanding of demand. To provide a standardized frame of reference, the EMG measured during each posture was “normalized” to the EMG that resulted from walking, by dividing the maximum EMG signal developed during the posture on the maximum EMG signal invoked during walking.

Bottom Line:
Understanding the physical demands placed upon the musculoskeletal system by individual postures may allow experienced instructors and therapists to develop safe and effective yoga programs which reduce undesirable side effects.They then performed the asanas in a motion analysis laboratory.Profiles illustrating the postures and including the biomechanical data were then generated for each asana.

ABSTRACTUnderstanding the physical demands placed upon the musculoskeletal system by individual postures may allow experienced instructors and therapists to develop safe and effective yoga programs which reduce undesirable side effects. Thus, we used biomechanical methods to quantify the lower extremity joint angles, joint moments of force, and muscle activities of 21 Hatha yoga postures, commonly used in senior yoga programs. Twenty older adults, 70.7 years ± 3.8 years, participated in a 32-wk yoga class (2 d/wk) where they learned introductory and intermediate postures (asanas). They then performed the asanas in a motion analysis laboratory. Kinematic, kinetic, and electromyographic data was collected over three seconds while the participants held the poses statically. Profiles illustrating the postures and including the biomechanical data were then generated for each asana. Our findings demonstrated that Hatha yoga postures engendered a range of appreciable joint angles, JMOFs, and muscle activities about the ankle, knee, and hip, and that demands associated with some postures and posture modifications were not always intuitive. They also demonstrated that all of the postures elicited appreciable rectus abdominis activity, which was up to 70% of that induced during walking.